Twitter reaction was swift and wide Wednesday to President Donald Trump's fallout with Steve Bannon over the former chief strategist's unflattering comments in an upcoming book, with Senate Majority Leader Mitch McConnell posting a smug tweet from his official account.

Bannon has vowed to remove McConnell as majority leader — and the senator ripped Bannon last month as a "genius" for backing Alabama Republican Senate candidate Roy Moore, who lost to Democrat Doug Jones in a hotly contested race amid sexual assault allegations against Moore.

The Trump-Bannon feud erupted Wednesday after The Guardian published excerpts of an upcoming book by Michael Wolff, "Fire and Fury: Inside the Trump White House," that includes many scathing comments from the former chief strategist.

Bannon, who was fired last August and has since returned to Breitbart News as executive chairman, described a 2016 Trump Tower meeting between Donald Trump Jr., Trump campaign aides and a Russian lawyer as "treasonous" and "unpatriotic."

Bannon also said that a "zero" percent chance existed that President Trump himself did not know of the meeting at the time.

New York magazine also adapted the book for publication on Wednesday.

President Trump hit back hard, saying in a statement that when Bannon was fired last year, "he not only lost his job, he lost his mind."

"Steve Bannon has nothing to do with me or my presidency," Trump said in the statement. "When he was fired, he not only lost his job, he lost his mind.

"Steve was a staffer who worked for me after I had already won the nomination by defeating seventeen candidates, often described as the most talented field ever assembled in the Republican Party," Trump said.

In commenting on the fracas toCNN, former Pennsylvania Republican Sen. Rick Santorum told Brooke Baldwin that "when you punch the president, the president punches back — and he's punching back.

"You can cast aside anything he said in the past as probably appropriate for that moment, and this is appropriate for when someone attacks him."

Santorum said Wolff's book proved to him that "the situation at the White House was as bad as everybody thought it was. Maybe worse when the president took office during the transition.

"When you work for this president," Santorum continued, "loyalty is the most important thing.

"If you turn on the president, he will turn back on you.

"Those are just two things to keep in mind if you'll end up going to work for Donald Trump," the former senator said.

Tweets on the dust-up spanned the political spectrum:

I guess that book launch party the White House was planning for Steve Bannon is off?

Twitter reaction was swift and wide Wednesday to President Donald Trump's fallout with Steve Bannon over the former chief strategist's unflattering comments in an upcoming book, with Senate Majority Leader Mitch McConnell posting a smug tweet from his official account.